CRUSTACEANS Chirocephalus diaphaiius, Prevost, in pools on Blackheath, a locality which, if now in the county of London, in those days belonged to Kent. This species, though very similar in structure to the Apus, is through the absence of the shield very different in appearance. Also its eyes are stalked instead of sessile, and its feet are reduced to the more moderate number of eleven pairs. The second antennae of the male form large claspers, thus accounting for the generic name which im- plies that the head is furnished with hands. The specific name alludes to the beautiful translucence of the animal. Its eggs, like those of many other freshwater Entomostraca, can remain a long time in dried mud without losing the capacity of developing subsequently in water. The Cladocera, a second subdivision of the Branchiopoda, are named from the branching second antennae which are their locomotive appendages. They furnish the fresh waters of all counties with numerous species. In Kent about a score of species have been catalogued, several of them quite recently through the assiduity of Mr. D. J. Scourfield, editor of the Journal of the Quekett Microscopical Club. It happens that all these species are included in one tribe, called the Anomopoda because they have their five or six pairs of feet not all alike, the first two pairs being, in contrast to those which follow, more or less prehensile and without branchial laminae. The tribe is divided into four families, among which the known Kentish species are repre- sented as follows. The family Daphniidae no doubt contributes Daphnia pulex (de Geer), since that species, according to Baird ' lives in almost all pools, and ditches of standing water, round London, etc." But this commonest of species is not free from perplexities, as will be seen by those who study the synonymy in Lilljeborg's great work on the Cladocera of Sweden. Baird establishes two other species of the genus D. psittacea from ' Pond on Blackheath ' and D. schoefferi from ' Pond on Bexley Heath, Kent, August and September, 1849. In addition to these D. obtusa, Kurz, is reported from Keston by Mr. Scourfield, and a variety propinqua of the same species by Dr. G. S. Brady from the neighbourhood of Tunbridge Wells. This variety was originally dis- tinguished as a separate species by Professor Sars, who reared it out of dried mud sent him from South Africa.' Baird's D. schoefferi is identi- fied by Brady with the earlier D. magna, Straus, which he refers to a new genus Dactylura, but this is cancelled by Lilljeborg, who identifies Baird's species and that of Straus with the yet earlier D. pennata (O. F. Miiller). As to Baird's D. psittacea, Brady says, it ' is quite unknown to me, though noted by some continental authors.' * Lilljeborg confesses to have confused it at first with Baird's later JD. atkinsoni, but now describes and figures it under its own name, with the recognition that Jules Richard had already distinguished it from £). atkinsoni in exemplary • British Entomostraca, p. 29. ' Loc. cit. pp. 93, 95. 3 Brady, Nat. Hist. Trans. Northumberland, Durham, and Neuuastle-upon-Tyne, xiii. pt. 2, 225 (1898). ♦ Loc. cit. 244. 253
